Use of HIV and HSV-2 biomarkers in sub-saharan adolescent prevention research: a comparison of two approaches.

Self-report of sexual behavior among adolescents is notoriously inconsistent, yet such measures are commonly used as outcomes for human immunodeficiency virus (HIV) prevention intervention trials. There has been a growing interest in the use of HIV and other sexually transmitted disease biomarkers as more valid measures of intervention impact in high HIV prevalence areas, particularly in sub-Saharan Africa. We examine the challenges, benefits, and feasibility of including HIV and herpes simplex virus type 2 (HSV-2) biomarker data, with details about different data collection and disclosure methods from two adolescent prevention trials in Kenya and Zimbabwe. In Kenya, whole blood samples were collected using venipuncture; adult guardians were present during biomarker procedures and test results were disclosed to participants and their guardians. In contrast, in Zimbabwe, samples were collected using finger pricks for dried blood spots (DBS); guardians were not present during biomarker procedures, and results were not disclosed to participants and/or their guardians. In both countries, prevalence in the study samples was low. Although the standard of care for testing for HIV and other sexually transmitted infections includes disclosure in the presence of a guardian for adolescents under age 18, we conclude that more research about the risks and benefits of disclosure to adolescents in the context of a clinical trial is needed. Notably, current serological diagnosis for HSV-2 has a low positive predictive value when prevalence is low, resulting in an unacceptable proportion of false positives and serious concerns about disclosing test results to adolescents within a trial. We also conclude that the DBS approach is more convenient and efficient than venipuncture for field research, although both approaches are feasible. Manufacturer validation studies using DBS for HSV-2, however, are needed for widespread use.